Why was MH17′s flight path over an area of fighting?

The downing of flight MH17 by a missile has raised a lot of questions about why a commercial plane was flying over Crimea and whether whoever shot the missile could tell it was a passenger flight.

We spoke to our Science Correspondent Miles O’Brien, a pilot himself, about these questions.

In April the Federal Aviation Association (FAA) prohibited only U.S. aircraft carriers from flying over parts of Ukraine. However, as O’Brien explained, this didn’t apply to the Malaysian flight which was north of the banned area.

“Flight MH17 was in an area it was allowed to be in. Malaysia had no specific prohibitions or regulations in this area,” said O’Brien.

Moreover some international carriers may defer to guidance already issued by European regulations or the FAA in these situations, explained O’Brien, because they have the capabilities to determine when air space is safe or not. Earlier this week a Ukrainian fighter jet and transport airplane were shot down in the same area. Yet, it was still technically legal though for MH17 to be flying there.

Even though it was legal, the flight path was above hostile fighting. O’Brien explained cost and time issues play a role in determining flight paths which might be why this one was chose.

“Everyone wants to avoid Iran air space,” said O’Brien, “So from most European capital cities to Southeast Asia the most direct route is over Ukraine. This would cost the least amount and get customers to their destinations as quickly as possible. When airlines say safety is the top priority, well, this shows that’s not always true.”

The flight path of MH17 may not have been the safest choice, but it was still flying at an altitude of around 33,000 feet on a route used by multiple aircraft everyday. In fact, a few aircraft were in the same general area when MH17 was shot down. Airliners mistakenly assumed from the frequency of flights and the high altitude that the path was safe.

“Every aviation expert knows there are surface to air missiles that have the capacity to hit a place at that altitude. Of course there are more missiles that can reach in the 10,000-foot range,” said O’Brien. “But we’re talking about the former Soviet Union here – they have the capacity to hit a plane that high on both sides of the border.”

If commercial flights were still allowed on this path and MH17 was flying at a normal altitude, could whoever fired the missile tell that this was a commercial flight filled with passengers? O’Brien says that is a bit more complicated.

When a flight is identified on a radar it is often assumed it comes up as “friend” or “foe”. O’Brien said, in fact, it will come up as friend, but not necessarily as foe.

“Military planes each have an encryption code they put in their planes so when it’s detected by radar you can automatically tell if they’re a friend. This is to avoid friendly fire during war. Commercial planes don’t have the same capability. It still shows up on radar whether they are ‘friends’ or not, but it doesn’t necessarily say they are an enemy. There is no black hat on blips saying this is an enemy. That’s when you get into a ‘shoot first, ask later’ mentality.”

By a deduction process – based on the flight path and the altitude – O’Brien said you could have concluded this was a commercial plane posing no threat.

“That’s where it requires human experience and knowledge in these situations. The flight doesn’t come up as a friend on radar, but you can determine that it was probably a commercial flight.”

O’Brien pointed out that although the air space was frequently used and MH17 was at a regular altitude, there is always the chance a plane could lose air compression or another problem that would require it to drop to around 10,000 feet. That kind of action could easily have been interpreted as threatening.

“It was a conscious decision by the airlines to fly this route. Whether they were trying to save fuel or get to their destination as quickly as possible – that shouldn’t compromise safety,” said O’Brien. “I hope the lesson has been unfortunately learned here.”